CloudPlug, a plug computer developed by CTERA Networks
Seagate Dockstar, a plug computer similar to the SheevaPlug
A plug computer is an external device, often configured for use in the home or office. The external device is a compact computer server. It consists of a (solid state) hard disk, along with control software and several ports (USB ports, ...). It remains an external device however and no keyboard or screen can be connected. It is hence only suitable for running a media server, back-up services, file sharing and remote access functions, such devices can be used as a bridge between in-home protocols such as Digital Living Network Alliance (DLNA) and Server Message Block (SMB) and cloud based services.
The name "plug computer" is derived from the small configuration of such devices: plug computers are often enclosed in an AC power plug or AC adapter.
Plug computers typically consume little power and are inexpensive. One manufacturer claims its $119 plug computer draws 1.2 watts and can cost $2 a year to run. The low cost of plug computers has led to a proposed "FreedomBox", an always-on home server configured to keep communication private in the face of government surveillance.